1. Field of the Invention
The present invention relates to a portable radio communication terminal designed for allowing a predetermined emergency call station to monitor the status of a user and its ambient conditions over a public radio telecommunications network and to a call center apparatus provided at the emergency call station.
2. Description of the Related Art
FIGS. 28 and 29 illustrate a conventional portable radio communication terminal and a communications system including the conventional portable radio communication terminal respectively. FIGS. 30A and 30B show an action of the system. The system consists mainly of the portable radio communication terminal 1PA, a call center 2, a police station 3, a group of GPS satellites 4, a radio communications line base station 5, and a public communications network 6.
The portable radio communication terminal 1PA comprises a radio transmitter/receiver 11 for transmitting and receiving signals over the public radio communications network, a microphone 12 and a loudspeaker 13 for producing and emitting the transmitting and received signals of the radio transmitter/receiver 11, a light emitter 14 for emitting light to display the action, an operation entry unit 15PA, and a controller 10PA for starting the transmission of a signal via the radio transmitter/receiver 11 to the predetermined emergency call station in response to the action of the operation entry unit 15PA for emergency call. The emitter 14 provides various indications including the storage level of an electric cell(s), the switching on of the signal transmission, and the intensity of a received signal showing “out of range” or “in range”.
The system permits the user to communicate with the call center 2 from the radio transmitter/receiver 11 over the public radio or cable communications network 6 through operating the operation entry unit 15PA of the conventional portable radio communication terminal 1PA. In turn, a reply of voice sounds from the operator at the call center 2 can be heard from the loudspeaker 13 as shown in FIG. 30B (where the reply indicates “What is wrong?”) with the emitter 14 flashing on and off.
However, when the operation entry unit of the conventional portable radio terminal is operated by the user to produce an emergency call for reporting, e.g., robbery or kidnapping, the loudspeaker as a voice sound releasing means releases a voice sound and the light emitter as a light emitting means emits flashing or continuous light. This may allow the criminal to notice the sending of the emergency call hence creating a more risky situation.